Flexible floor covering with non-slip properties, and production method thereof

ABSTRACT

The floor covering of the type comprising non-slip particles in its surface layer is remarkable in that the covering is made from a flexible and resilient material, and in that said particles are formed by a crushed glass core, the surface of which is fully or partially covered with a metal covering, the said particles being sprinkled in a flexible PVC base with no finishing work.

This invention relates to the technical sector of floor coverings.

Floor coverings, depending on their use, must fulfil three main functions namely slip resistance, maintainability and the possibility of choosing decorative appearances that can vary from a light to a dark aspect.

Non-slip resilient flexible floor covering must fulfil a certain number of functions relating to the standard to which it refers, in particular, it must meet Standard EN 13845 and UK Health and Safety Executive requirements in terms of non-slip properties and wear resistance. The covering must in particular obtain the Esf (≧20°) and Esb (≧15°) Classification in accordance with Appendix C of Standard 13845.

FIG. 1 is a schematic diagram of the composition of a floor covering structure with a surface (1) loaded with non-slip particles (1 a) and polyvinyl chloride granules in order to form the decorative surface, then the coating complex (2) then the charged polyvinyl chloride backing (3).

This product has a surface treatment for easy maintenance It has non-slip particles throughout its entire wear layer, including in the surface treatment, ensuring slip-resistance for the entire lifetime of the floor covering.

The proposed floor covering is produced by coating:

-   -   coating with a so-called PVC plastic back coating on a glass         grid complex and a non-woven polyester cellulose layer;     -   coating with surface PVC plastisol;     -   sprinkling with decorative PVC granules;     -   sprinkling with non-slip particles as a decorative feature;     -   a sprinkling of surface treatment;     -   a re-sprinkling of non-slip particles.

Thus, depending on the standard set, the product has a quantity of non-slip particles of at least 75 g/m² in the wear layer associated with the surface treatment. The particles are sprinkled evenly in accordance with a known technology.

Non-slip flexible floor coverings as such are thus known and have a similar construction. They have, in their wear layer, non-slip particles harder than the plasticised polyvinyl chloride material.

These particles are usually mineral in origin and, depending on their characteristics, have advantages in certain cases but also some drawbacks.

CSi silicon carbide particles are the most widely used. They are very hard (9 Mohs) and have a very high resistance to abrasion. The particle, which is angular, gives the floor covering its non-slip quality. Moreover, these particles have a glittering effect. The use of these extremely hard particles has numerous drawbacks. In particular, floor coverings that contain them are very difficult to recycle: the hard particles of the polymer matrix must be separated so as not to damage conventional processing equipment. Furthermore, the life cycle analysis of silicon carbide is very unfavourable because its synthesis is very energy-intensive with high GHG emissions. Lastly, the black appearance of this CSi particle limits the decorative appearance of the floor covering.

The use of a metal particle consisting of Aluminium Trioxide, commonly called ‘CORUNDUM’, is therefore known. Its use has the advantage of hardness equivalent to CSi and ensures the non-slip function of the floor covering. Its appearance lies within a colour range of white to brown. The drawback also lies in the difficulty of recycling, an unfavourable life cycle analysis and the absence of a glittering appearance.

The use of natural sand is also known with, in its turn, advantages and drawbacks. The advantages basically relate to its life cycle analysis, with an absence of heavy industrial processing. Hardness is still considerable (7 Mohs). Sand particles are angular and so advantageous due to their non-slip properties. Lastly, the sand particle can be coloured, which is important for decorative appearance.

By contrast, coverings containing these particles are difficult to recycle because they are too hard. Furthermore, sand contains crystalline silica causing silicosis and requiring major industrial developments.

The use of PA or PMMA polymer particles is also known. In this case, these types of particles enable a non-slip quality to be achieved. Floor coverings that contain them can be recycled depending on the temperature at which these particles melt. They enable a wide range of shapes and decorative effects to be achieved. Their main drawback lies in their very poor hardness compared to mineral particles, giving them a low resistance to wear. Also, another restriction lies in their chemical compatibility, which is not necessarily compatible with the production matrix.

Furthermore, document WO 01/19624 discloses a rigid material (concrete and marble and sand aggregates) into which are sprinkled metal particles which are then sanded to give a decorative appearance.

According to patent EP 0 521 286, the product is a tile, the surface of which undergoes a sanding or grinding operation.

The use of particles made from ground glass is thus known. The advantages lie in their considerable hardness (6 Mohs) sufficient for floor coverings. These particles are obtained from recycling so that the finished product can be recycled. The particle is transparent. By contrast, the drawbacks of using particles made of ground glass are considerable with a low resistance to wear, a limited decorative appearance with raw glass and the impossibility of obtaining a glittering appearance.

Thus the analysis of all of these types of particles, which can be and are used in these floor coverings, show that it is very difficult to produce a floor covering that has the various above-mentioned functions and is also recyclable.

The Applicant's approach has therefore been to bear in mind the technical and economic limitations resulting from the known use of the above-mentioned particles by aiming to meet the various criteria of slip-resistance, maintainability, decorative variation with a glittering appearance and also the possibility of recycling the floor covering under the best technical and economic conditions.

This approach has led to the implementation of floor coverings that satisfy all of these parameters by designing non-slip particles that enable these parameters to be achieved.

The solution devised by the Applicant lies in a particular selection and design of non-slip particles which are projected and sprinkled in an identical way to the prior practice.

The design and selection of these specific particles according to the invention result from an optimised process for implementing a specific method of producing said particles.

Thus, according to a first characteristic of the invention, the floor covering of the type comprising non-slip particles in its surface layer is remarkable in that the covering is made from a flexible and resilient material, and in that said particles are formed by a crushed glass core, the surface of which is fully or partially covered with a metal covering, the said particles being sprinkled in a flexible PVC base with no finishing work.

According to another characteristic, the metal covering on all or part of the core of crushed glass particles is copper, stainless steel, aluminium, brass, silver or gold.

According to another characteristic, the method consisting in depositing the metal covering over all or part of the glass core of each particle is performed under vacuum, by PVD (Physical Vapour Deposition).

These and further characteristics will clearly emerge from the following description.

A non-limiting description of the subject matter of the invention is shown in the accompanying drawings, in which:

FIG. 1 is a schematic diagram of the structure of a conventional floor covering with a non-slip effect;

FIG. 2 is a diagram with three axes evaluating the products of the prior art and that obtained by the implementation of the invention according to the three criteria: slip-resistance, decorative effect and maintenance;

FIG. 3 is a top view of a sample of floor covering containing silicon carbide and showing its appearance;

FIG. 4 is a top view of a sample of covering containing the particles according to the invention;

FIG. 5 is a schematic view of a particle according to the invention.

In order to provide a more concrete explanation of the subject matter of the invention, a non-limiting description thereof now follows with reference to the accompanying drawings.

The floor covering made of flexible and resilient material contains in its flexible surface layer with a PVC base according to the invention non-slip particles (P) shown in FIG. 5 which comprise a ground glass core (4) the outer surface of which is fully or partially covered with a metal covering (5). Said particles are sprinkled in the flexible PVC base with no finishing work.

This covering can be of copper, stainless steel, aluminium, brass, silver, gold or other substances. The choice or nature of the metal material also depends on the application of the floor covering in question and the desired technical and visual effects. This metal covering can cover all or part of the surface of each non-slip particle, depending also on the desired criteria and requirements.

According to the invention, the floor covering may contain these particles evenly distributed, but may also concentrate them in specific areas to suit requirements. It is also possible to combine them with other ground glass particles not covered in metal material and in proportions that may, for example, be 50/50. These particles are of the same size as that adopted by the prior art.

The production of these particles according to the invention can be performed in any appropriate way. However, the solution of the invention consists in depositing a metal covering on the ground glass cores by using the vacuum technique, known as PVD.

The solution devised by the Applicant is particularly attractive and innovative compared with the prior art.

The solution proposed by the Applicant involves no finishing work, sanding or post-treatment.

The new non-slip particle according to the invention has a surface treatment enabling it to meet the following requirements:

-   -   good compatibility with polyvinyl chloride (PVC) and glass;     -   non-slip properties preserved;     -   unique metal appearance conveying a glittering and light         appearance;     -   limited soiling of the product because the surface treatment of         the particle limits soiling;     -   the floor covering is recyclable because the hardness of the         particle is less than that of the particles used in the prior         art, as mentioned, CSi, corundum, sand, etc.

FIGS. 3 and 4 show the different appearances achieved using a floor covering with silicon carbide particles and those according to the invention with a ground glass core receiving a surface treatment by metal deposition over all or part of its volume.

In the diagram in FIG. 2, the OX axis shows the conditions of difficult to easy maintenance. The OY axis shows the conditions of maintenance from slippery to very non-slip. The OZ axis shows the conditions of decorative appearance from dark to light.

Three products of the prior art EA1, EA2 and EA3 are thus evaluated, together with that of the invention G.

In EA1, the non-slip particles are black CSi particles. The decorative effects are therefore very limited because they are darkened by the silicon carbide. Maintenance poses less of a problem because the carbide gives a pre-soiled appearance.

In product EA2, the non-slip particles are white or transparent (corundum, quartz, sand, raw glass) which affords clear and rich decorative appearances.

However the coverings soil rapidly and are difficult to clean.

Product EA3 contains no non-slip particles. There is a varied choice of colours, maintenance is easy due to a lack of roughness. By contrast, there is a problem of slipperiness when wet. These products do not meet the above-mentioned requirements of the HSE and EN 13845.

The floor covering G, according to the invention, is evaluated in the diagram in a combined optimisation of all three criteria.

The slip tests performed with the aid of a pendulum test enable the floor surface's capacity to stop the pendulum when the slide chafes to be measured and shows that the floor covering according to the invention has excellent non-slip properties without penalising its roughness, which makes it easier to clean and less easy to soil.

The advantages clearly emerge from the invention. The novel and unexpected design of the non-slip particles in this specific application of flexible floor covering is emphasized together with the consequent advantages, particularly the possibility of being recycled. The use of these types of vacuum-treated particles to obtain non-slip and decorative performance is particularly novel since no product of this type exists and the above-mentioned documents of the prior art do not suggest such a solution.

The method of depositing and treating the surface by vacuum-deposition of the metal covering is also unexpected. This known technique is reserved for high-technology products and the application of this vacuum method was not obvious to perform and master for this type of application. 

1. Floor covering of the type comprising non-slip particles in its surface layer characterized in that the covering is made from a flexible and resilient material, and in that said particles are formed by a crushed glass core, the surface of which is fully or partially covered with a metal covering, the said particles being sprinkled in a flexible PVC base with no finishing work.
 2. Floor covering according to claim 1, characterized in that the metal covering on all or part of the core of crushed glass particles is copper, stainless steel, aluminum, brass, silver or gold.
 3. Floor covering according to claim 1, characterized in that it comprises in its surface layer metal particles formed by a crushed glass core which are fully or partially covered with a metal material and particles formed by crushed glass cores without a metal covering.
 4. (canceled)
 5. Floor covering according to claim 2, characterized in that it comprises in its surface layer metal particles formed by a crushed glass core which are fully or partially covered with a metal material and particles formed by crushed glass cores without a metal covering. 